The answer to this depends to some degree on the type of job in question. However, we can make some general observations that apply to most American jobs.
The major global issue that affects compensation in the United States is globalization. Globalization has created much more competition between firms around the world. This has affected compensation in two major ways. First, it has tended to reduce compensation for those workers whose jobs compete directly with overseas workers. As global competition heats up, workers at such firms as the “Big Three” auto manufacturers in the US can no longer expect to receive the lavish compensation that they received some decades ago when competition was less intense. Second, however, globalization has had an opposite impact on the compensation of some of the top people in various industries. With the opening of global markets, firms can make more money by selling in many countries. This means that the top people can get more money because the things that their firms create can be sold more broadly. This has led to a situation in which the people in the best jobs are making more and more money while the people in lower jobs are often making less since they have to compete with people around the globe.